s and then photographing it
by transmitted light while it is still impregnated with the xylene. If
the substance dries too fast to permit proper photographing, the skin
should be photographed while immersed in the xylene. (See subtopic of
this chapter pertaining to "general photography.") Of course, after
the skin has been photographed the negative should be printed to give
a reverse position so that the print will be comparable with inked
impressions on fingerprint cards.

_Desiccation and charring_

The problem confronting the fingerprint examiner in treating fingers
which are desiccated or dried and shriveled is that of distending and
softening the skin. Desiccated fingers are generally found to have the
outer layer of skin intact and the ridge detail fairly clear. However,
due to the shrinking, numerous wrinkles will be present, and as the
drying process continues the skin and flesh harden until the fingers
become almost as hard as stone.

It is sometimes possible to distend or swell the flesh by utilizing a
1- to 3-percent solution of sodium hydroxide or potassium hydroxide,
sometimes referred to as caustic potash. As a matter of caution, this
process should be tried with one finger before using it for the
remaining fingers. This point of caution is made because of the
reaction of the potassium or sodium hydroxide, which is actually one
of destruction. While absorption and swelling of the flesh occur, the
disintegrating action of the fluid may result in total destruction of
the flesh.

The finger to be distended is cut from the hand at the second joint
and placed in the hydroxide. When it has resumed its normal size by
the absorption of the solution, it is inked and printed. There is no
set time for this process. The procedure may require a few hours or as
much as several days until suitable results are obtained.

After the finger has been in the solution for about 30 minutes, it
should be removed and examined in order to note the extent of the
swelling and the reaction of the flesh to the solution. If no material
change is noted, the finger is returned to the solution. A close watch
is maintained and the finger is examined from time to time.

The solution may cause thin layers of skin to peel from the finger.
Should this occur, the loose skin is carefully scraped off and the
finger rinsed in water for a few minutes. It is then returned to the
hydroxide for continuation of the process.

If, during the co